1. Field of the Invention
The present invention relates to electronic device cooling technology and more particularly, to a cooling device consisting of a radiation fin unit comprising a plurality of radiation fins, a heat sink base, a cooling fan unit and a plurality of thermal tubes, wherein each radiation fin comprises a plurality of first wind guiding wall portions and second wind guiding wall portions respectively tilted in reversed directions to facilitate the flow of air through heat-dissipation passages in the radiation fin unit.
2. Description of the Related Art
Following fast development of computer technology, powerful, high-speed, inexpensive computers with large capacities have been continuously created. In consequence, computer related applications have also been well developed. As clock frequencies in digital circuits and voltage applied increase, the heat generated by components running at the higher performance levels also increases. It requires more effective cooling to avoid damaging the hardware by overheating. Many heat sinks and cooling devices have been created for the purposes of cooling computer components.
A conventional cooling device is known, as shown in FIG. 8, comprising a heat sink A attachable to, for example, a CPU B1 on a circuit board B to absorb waste heat from the CPU B1, and a cooling fan C attached to the heat sink A for creasing a flow of air to carry waste heat away from the heat sink A. The heat sink A is a one piece member made of aluminum or copper alloy by using extrusion or molding technology, comprising a flat base A1 and upright radiation fins A2 upwardly protruded from the flat base A1 and equally spaced from one another. The cooling fan C is mounted on the flat top edges of the upright radiation fins A2. During operation, the flat base A1 absorbs waste heat from the CPU B1 and transfers absorbed waste heat to the upright radiation fins A2. At the same time, the axial flow of air created by the cooling fan C is forced toward heat-dissipation passages in between each adjacent ones of the upright radiation fins A2. According to this prior art design, the central area of the flat base A1 of the heat sink A is directly attached to the surface of the CPU B1 to absorb waste heat from the CPU B1 and to transfer absorbed waste heat to the border area of the flat base A1 and the upright radiation fins A2. Thus, the temperature of the central area of the flat base A1 of the heat sink A is always much higher than the border area of the flat base A1, lowering the head dissipation efficiency of the cooling device.
Further, the design of the upright radiation fins A2 of the heat sink A is to crease the radiation surface area. Further, in order to increase the radiation surface area, the upright radiation fins A2 are arranged in a high density manner within the limited surface area of the flat base A1. In consequence, a certain level of wind resistance is produced upon flowing of the created axial flow of air through the heat dissipation passage between each two adjacent upright radiation fins A2, leading to a high level of fan noise. Further, because the flat top edges of the upright radiation fins A2 are kept in flush, the axial flow of air created during operation of the cooling fan C is concentrated on and forced toward the central area of the heat sink A, lowering heat dissipation efficiency.
Therefore, it is desirable to provide a cooling device that eliminates the drawbacks of the aforesaid prior art design.